This study plan delineates the execution strategy for race and ethnicity research in the 2015 National Content Test (NCT). First, we lay out the purpose of the 2015 NCT, including a brief overview of the content test. Second, we review relevant literature, with particular emphasis on the 2010 Census Race and Hispanic Origin Alternative Questionnaire Experiment (AQE). Third, we provide a detailed description on the methodology of the 2015 NCT as it pertains to race and ethnicity. Fourth, we present a detailed description of the research dimensions that will be explored and a series of research questions, table shells, and decision criteria for making recommendations on the results. Finally, we provide a list of potential limitations, a milestone schedule, document logs, and detailed appendices.